If you're not familair with Juval Lowy, he's one of our Regional Directors and writes some great content that you can find in a number of areas (including MSDN online and in print).

He's just released an article on WCF instance management techniques - check it out here.

http://msdn.microsoft.com/winfx/default.aspx?pull=http://msdn.microsoft.com/msdnmag/issues/06/06/WCFEssentials/default.aspx